In transmitters based on a direct conversion transmission technology, a possible topology is to use a harmonic Voltage Controlled Oscillator (VCO) in which the VCO frequency is twice or 4 times the center frequency of the transmitted signal at the power amplifier (PA) output. This topology helps to prevent Spurs and allows for an efficient implementation. However, one disadvantage of such a topology is that the harmonics of the transmitted signal fall on the VCO frequency (e.g. the 2nd harmonic if the VCO is at twice the transmitted frequency or the 4th harmonic if it is at four times the transmitted frequency) and might alter (“pull”) its frequency and thus degrade the local oscillator (LO) phase noise (PN). This effect is called pulling injection. Although the power amplifier of the transmit chain using the VCO is one source of pulling injection. Further, all types of oscillators may be affected, for example also digitally controlled oscillators (DCO's or NCO's). All types of oscillators using a phase control loop to stabilize an oscillator output are subsequently named controlled oscillators. In next generation implementations, pulling injection is likely to be increased if the die size is going to be shrunk, bringing the PA closer to the VCO. It is desirable to mitigate the effects of pulling and, for example, to decrease the phase noise of a controlled oscillator.